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psi

1
[sahy, psahy]
noun, plural psis.
  1. the 23rd letter of the Greek alphabet (Ψ, ψ).
  2. the group of consonant sounds represented by this letter.
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Origin of psi

1
1350–1400; Middle English < Greek pseî

psi

2
[sahy]
noun
  1. any purportedly psychic phenomenon, as psychokinesis, telepathy, clairvoyance, or the like.
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Compare pseudoscience, parapsychology.

Origin of psi

2
1940–45; shortening of psychic or parapsychic
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for psis

Historical Examples of psis

  • "You'd sure look silly if all the Psis in town blackballed you," I snarled at him.

    Modus Vivendi

    Gordon Randall Garrett

  • "Nobody forced her to associate with a gang of Psis," he said.

    Modus Vivendi

    Gordon Randall Garrett

  • Crescas appeared as if by magic—Psis act like that—and had me by the arm.

    Modus Vivendi

    Gordon Randall Garrett

  • His black eyes had that lively watchfulness you associate with Psis.

    Modus Vivendi

    Gordon Randall Garrett

  • Their attire, their homes, everything about Psis, seems tasteful.

    Modus Vivendi

    Gordon Randall Garrett

British Dictionary definitions for psis

PSIS

abbreviation for (in New Zealand)
  1. Public Service Investment Society, New Zealand's largest credit union
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psi

1
abbreviation for
  1. pounds per square inch
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psi

2
noun
  1. the 23rd letter of the Greek alphabet (Ψ, ψ), a composite consonant, transliterated as ps
    1. paranormal or psychic phenomena collectively
    2. (as modifier)psi powers
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Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for psis

psi

n.

23rd letter of the Greek alphabet. Use for "psychic force, paranormal phenomenon" dates from 1942 (probably from psychic (adj.)).

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Online Etymology Dictionary, © 2010 Douglas Harper
psis in Medicine

psi

(sī, psī)
n.
  1. The 23rd letter of the Greek alphabet.
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The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.